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Homework Help: Simple Silent Alarm

  1. Mar 4, 2006 #1
    I am interested in building a simple silent alarm for a door. All I want to do is set up a system so that a light will blink when the door is opened. I am trying to set this up in a school building for when another teacher enters the room unexpectedly. I'm a TA and it makes it very difficult not to get the teacher in trouble when she keeps coming in and no one notices. Thanks!
  2. jcsd
  3. Mar 5, 2006 #2


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